Cam be that EmEditor and EditPad use different regular expression engine that does not support greedy request as you one, and treat it as non greedy. Or limit to lien scope.Try to modify it to non greedy (I do not think that you really want greedy version): a.*?bkstfwxlhsdgdhlsgfdgsf

If does not help, I can check once more, but than I need reproducible example.

okay, thanks for the explanation. Previously, I didn't even know what Greedy means. Adding the question mark to my regular expression, as you suggested, fixed the slowness problem.

I've made some further tests with EmEditor and EditPad Pro. They both support Greedy. And by default they both limit to line scope, which is the reason why they don't have the slowness problem with my original regular expression. And they both have an option by which you can choose whether the dot will match a newline character. In EmEditor, this option had no effect in my tests. In EditPad Pro, it behaved as expected. When I turned the option ON, search became much slower (but still not as slow as in HippoEdit).

So to summarize, there is no bug in HippoEdit here. And as a future enhancement suggestion, maybe you could add an option "dot will match newline character". I would turn that option OFF by default.

actually I am trying to simplify and reduce number of options everywhere (especially in search dialog - it "lost" several not used options in 1.51). So, I will be strongly against of any not highly requested UI feature flag in search dialog.